Love the SP3 and would do backflips if I could get 5 hours. You should be able to get at least a full Westbound transcon out of it which was not close for me. I have not done all the suggestions, here, but I did get the IntocircuitŪ Power Castle PC26000. It's not light, but it is compact. I get at least one full charge out of it, and it gives me the freedom to travel that I wish the SP3 could deliver on its own. I popped for the warranty, so a trip back to the Microsoft store makes sense, too. Thanks for the suggestion.